When knitting a large fabric panel, it is often the case that the finished fabric will be cut into smaller pieces for use in a finished product, such as a window treatment. The cutting of fabric, however, introduces a number of problems which may present themselves during manufacture, most notably that extra steps are required to cut the fabric accurately. Likewise, by its very nature, cutting interrupts the fabric matrix, leaving a frayed edge which can undermine the strength or appearance of the fabric in the finished product.
In many window or see-through door applications, it is desirable to control the amount of light admitted through the window or see-through door. For instance on sunny days in warm climates, the sun is too strong (and too hot) for the comfort of the occupants, as well as being damaging to interior furnishings that may fade or become brittle. Typically, blinds are fitted, consisting of multiple slats of opaque material that can be individually rotated, in a coordinated manner, to block all or part of the light. When such slats are arrayed horizontally, the assembly is commonly called a “Venetian blind”.
In large windows or doors, venetian blinds are impractical because they can become difficult to raise completely when needed for unobstructed viewing, or to clean the glass behind. So, often a variant called a “vertical blind” is fitted, in which rotatable slats are hung vertically from their ends on a traverse mechanism with individual, coordinated rotating hangers. Vertical blinds have been most often used in settings where large windows are more common, such as in commercial buildings or for residential patio doors or picture windows.
Vertical blinds are well known and commonly comprise elongated strips or slats of opaque material suspended vertically from an overhead traverse mechanism provided with individual rotatable hangers. Conventional louvers, also called slats or vanes, of a vertical blind are adapted for lateral movement between a drawn blind position, in which the blind is opened to one or opposite ends of a traverse or channel adjacent their tops and an extended blind position wherein the louvers are positioned in generally equal spaced relation to one another along the length of the traverse or channel.
The louvers themselves are also adapted for selective rotation about their longitudinal axes between open and closed positions. The spacing between the louvers when the blind is extended is approximately equal to their width. Thus, when the traverse mechanism is positioned, for example, above and along the horizontal length of a window, the rotation of the louvers selectively blocks the passage of light through the window.
The vertical louvers may be made of vinyl or other suitable material, colored to add an accent color to the room or colored to blend with the primary color of the room. These louvers are generally limited to solid colors, or simple vertical patterns, because they are manufactured separately. If a continuous horizontal pattern effect is attempted using this method, it is prohibitively difficult accurately to align sequential louvers horizontally. Each louver in a horizontal pattern represents an individual pattern segment even slight misalignment of which would be unattractively obvious and would destroy the aesthetic appeal of the blind.
The louvers may also be made or covered with a fabric material to achieve a specific design effect. Louvers formed entirely of fabric may lack the rigidity of solid louvers, and thus may be provided with a hanger reinforcement at the top and a weight on the bottom to permit the louvers to hang uniformly.
Currently, fabric blind louvers are manufactured from continuous rolls of louver-width fabric that have been slit from wider fabric rolls. These are individually cut to length and sewn to form a louver. This production method makes the incorporation of a horizontal pattern prohibitively difficult because there is no way to assure that pattern elements will align horizontally. Even if the louvers were cut transversely from rolls of patterned fabric having a width equal to the length of the louver, further processing such as the attachment of mounting hardware to each of the louvers would introduce sufficient vertical error into each louver to destroy the horizontal alignment of the pattern.
Fabric louvers manufactured from a single roll of fabric have an additional drawback in the tendency of the louvers to fray along their longitudinal edges, particularly as a result of machine washing. Because the material from which the louvers are cut necessarily has an existing continuous structure, the cutting of which necessarily presents edges where the structure has been interrupted, resulting in a series of loose threads. Untreated, these threads tend to unravel, weakening the fabric and creating an unattractive frayed edge over time and as laundered. Preventing this result requires additional costly manufacturing steps.
It is also known to combine a vertical blind with a sheer fabric wherein the opaque vertical slats of the blind cooperate with the sheer fabric to provide diffusion of the light entering between the opaque slats when the blind has been extended and is in the open position. This provides an aesthetically pleasing effect, as well as adding privacy as a result of reduction in the clarity of view from the exterior into the interior of the building.
U.S. Pat. No. 5,638,880 to Colson et al. discloses such a combination vertical blind wherein rigid opaque vanes having the arrangement of a conventional vertical blind are attached at one of their longitudinal edges a sheet of sheer fabric such that light passing between the slats of the blind passes through the sheer fabric when the blind is open. Such a blind can be expensive to manufacture, as the sheer fabric must be attached to the vanes during an additional manufacturing step because the vanes are made of a different material from the fabric. Furthermore, although the width of a conventional vertical blind can be adjusted by adding or removing a number of discreet vanes, this is not possible in a combination blind because the vanes are essentially connected together into a single structure by the sheer fabric, requiring these blinds to be custom made to a specific width, also adding to their expense.
Another example of a combination blind is disclosed in U.S. Pat. No. 3,851,669 to Shapiro. Shapiro is directed to a drape adapted to be supported in the manner of a vertical blind and having alternate opaque and sheer vertical sections. The opaque sections are generally rigid and may be selectively rotated to permit the transmission of light through the sheer sections or to block the transmission of light by folding the sheer sections over the opaque sections. One obvious drawback, in addition to the drawbacks discussed with respect to Colson et al. above, is that the rigid vanes overlap the fabric requiring excessive fabric in order to fabricate the entire window covering. Further, the vanes or louvers are only attached to the fabric material along a top and bottom edge thereof, thereby inhibiting the control over the fabric material during operation of the window covering.
Another embodiment disclosed by Shapiro is a blind having alternating opaque and sheer sections in which the generally rigid vertically extending louvers are eliminated and substituted by a fabric panel having alternate vertical sections of fine and coarse mesh. The fine mesh sections may be provided with stiffening members at a top hem thereof and are connected to a vertical blind traverse from which the fine mesh sections may be rotated as louvers. When in the open position, the coarse mesh sections are disposed so as to admit a maximum of light therethrough. When in the closed position, the fine mesh sections are rotated so that the edges thereof overlap adjacent fine mesh sections to impede the transmission of light. Although this embodiment overcomes some of the limitations of the first Shapiro embodiment, a disadvantage of such a blind would be due to the lack of stiffness of the fine mesh “louver” sections. Any attempt to rotate the louvers of the second Shapiro embodiment would be resisted progressively along the length of the louver, resulting in an unattractive, non-uniform twisting which would render the blind nonfunctional.
Therefore a need exists for a vertical blind which can display a pattern horizontally across its louvers such that the alignment of the pattern from one louver to the next occurs without noticeable misalignment.
A further need exists for a vertical blind having louvers formed entirely of fabric, said louvers having an independent knitted structure wherein the major seams are substantially uninterrupted and free of loose thread ends, and wherein said louvers can be machine washed without developing frayed seams.
A still further need exists for a combination blind comprising a panel of fabric combining sheer and light-blocking sections, said blinds having sections of sufficient rigidity to function as louvers and a structure which allows the louvers to uniformly adjust to vary the amount of light which passes through the sheer sections of the blind, without the need for stiff louver panels.
A still further need exists for a fabric combination blind which can be produced in a standard width which can be adjusted easily as needed during installation over non-standard windows.